1. Field of the Invention
The subject invention relates to the field of measuring devices, and more particularly to devices for measuring the rotation rate of spherical objects with acoustic waves.
2. Description of the Prior Art
Presently, the rotational velocity of spherical objects is measured using optical methods or electrical fields. Optical methods require that the object be marked. Electrical methods require that the object be marked or that it be non-spherical, i.e., have an elliptical cross section, because such devices gauge rotation rate by sensing the variation of the capacitance with the distance between the object and an adjacent housing as a function of time.
The present invention avoids the aforementioned problems inherent in the prior art by introducing an acoustic wave at the surface of an object that propagates through the object. No contact is made with the object, it is not marked, it need not be electrically charged, and the object may be spherical.